Spark-plug tester



Jan. 22, 1929.

C. S. COLE SPARK PLUbr TESTER Filed March 22, 1927 WITNESSES Patented Jan. 22,1929.

cAnMaNs. COLE, or PENDLETON, onEeoN.

spaak-PLUG TESTER,-

Application led March 22, 1927. Serial No. 177,387.

M invention relates to a testing device for spar plugs andllas for its general object to provide a spark plug tester which may be employed to'test the spark under substantially the same degree of compression as. 1t will be subjected to in practice, whereby the tester will indicate defects of the s parkplug which ordinarily will not show up or be indlcated when the plug is tried out or tested when not under compression.

The nature of my invention and its distinguishing features and advantages will more clearly appear as the description proceeds. 1 l

Referencel is-to be had to the accompanying drawings forming a part of this specification, it bein understood that the drawings are merely illustrative of one example of the invention.

Figure 1 is a front elevation of a spark plu tester embodying my invention.

Figure 2 is a vertical section 1n a plane 1ndicated by the line and' arrows 2 2 in Figure 1. In carrying out my invention in accordance with the illustrated example a pump cylinder 10 is provided in which operates a lunger 11, the rod 12 of which has a suitable liandle 112 for operating the plunger. The ao numeral 13 indicates the air inlet ofthe ump.

The plunger 11 has a seat 14 at the top or the cup leather 1"5 held by nut 16.

On the pump cylinder 10 is mounted a head 17 having integral therewith a cap 18 which Vis threaded on to and forms a closure at the forward end of said cylinder. Said ca 18 has a discharge port 19 leading from in ront of the plunger 11.

A pipe 20 connects the discharge port 19 21, the valve in the illustrated form consisting of a known. construction. From the valve 21 a port 22 leads to a chamber 23 formed in the head 17, said chamber at one side being closed by the spark lug 24 screwed thereon when the plug is tob 23 at the front has a sight opening which in practice is provided vwith a lens 25 held in place by a screw cap 26. The chamber 23 1n practice connects by a pipe 27 with a pressure gage 28.

From the description and illustration of the assemblage it will be seen that air from the discharge port 19 of )the pump will pass by1 pipe 20 to the valve 21 and from said va ve of the pump with one end of a check valve e tested. The chamber.

by passage`22 to the chamber 23, the

pressure in said chamber 23 registeringy at the gage 28 by reason of the connecting pipe 27. This pressure ma be developed at the terminals of the sparlii plug in accordance with the pressure under which the plug is used in practice and the functioning of the 4 plug may be observed through the lens 25. Thus the plug will be caused to be tested as to its eiiiciency and operativeness under substantiall the same condition of pressure under w ich the plug will be employed when in actual use. In the use of the described tester the spar plug is first screwed into the head 17 and then the high tension lead from the booster mag-y neto is connectedto the spark plug as well as a ground lead from the tester to the base ofthe booster magneto. Then the pump, which it will be observed, is contained in the handle of the tester, is given a few strokes to build up pressure in the chamber 23. Then the booster crank is given a few turns and the firing of the s 'park plug is observed through the lens25. Thus the spark will be tested under pressure conditions approximately the same as those under which the spark plug operates in actual practice.

I would state furthermore that while the fillustrated example constitutes a practical embodiment of my invention, I do not limit myself strictly to the exact details herein illustrated, since, manifestly,the same can be considerably varied without departure from the spiritof the invention, as defined in the appended claims.

What I claim is: v

1. A spark plug tester in the form of a compact tool comprising a ump barrel constituting an elongated han le, a piston operating in the barrel, a head projecting from one end of the handle, the head having oppositely-disposed flat faces and openings in said faces, one of the openings having a transparen't closure, the otherl opening being adapted to receive a spark plug with the electrodes visible through the transparent closure, the head being provided with a chamber in communication with the opening and in communication with the pump barrel.`

2..A spark plug tester in the form of a compound tool comprising a pump barrel constituting an elongated handle, a piston operating in the barrel, a head projecting from one end of the handle and provided with a chamber, a conduit for placing the chamber in restricted communication` with the erated air pressure will be pro ucedwithin the chamber, .which fessure? will simulate' the pressure under whloh a spark must oper- 5 ate in the combustion chamber of an internal `in the conduit for maintaining such pressure in the chamber, thev head having a threaded opening to receive a spark plug, the head having a second openin opposite the t eaded 10 opening and provi ed with a tra sparent I `closure. combustlon engine, and a valve mtercalated CARM'AN s; COLE.' 

